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/*
* Authored by Alex Hultman, 2018-2020.
* Intellectual property of third-party.
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
* http://www.apache.org/licenses/LICENSE-2.0
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/* This module implements URI query parsing and retrieval of value given key */
#ifndef UWS_QUERYPARSER_H
#define UWS_QUERYPARSER_H
#include <string_view>
namespace uWS {
/* Takes raw query including initial '?' sign. Will inplace decode, so input will mutate */
static inline std::string_view getDecodedQueryValue(std::string_view key, std::string_view rawQuery) {
/* Can't have a value without a key */
if (!key.length()) {
return {};
}
/* Start with the whole querystring including initial '?' */
std::string_view queryString = rawQuery;
/* List of key, value could be cached for repeated fetches similar to how headers are, todo! */
while (queryString.length()) {
/* Find boundaries of this statement */
std::string_view statement = queryString.substr(1, queryString.find('&', 1) - 1);
/* Only bother if first char of key match (early exit) */
if (statement.length() && statement[0] == key[0]) {
/* Equal sign must be present and not in the end of statement */
auto equality = statement.find('=');
if (equality != std::string_view::npos) {
std::string_view statementKey = statement.substr(0, equality);
std::string_view statementValue = statement.substr(equality + 1);
/* String comparison */
if (key == statementKey) {
/* Decode value inplace, put null at end if before length of original */
char *in = (char *) statementValue.data();
/* Write offset */
unsigned int out = 0;
/* Walk over all chars until end or null char, decoding in place */
for (unsigned int i = 0; i < statementValue.length() && in[i]; i++) {
/* Only bother with '%' */
if (in[i] == '%') {
/* Do we have enough data for two bytes hex? */
if (i + 2 >= statementValue.length()) {
return {};
}
/* Two bytes hex */
int hex1 = in[i + 1] - '0';
if (hex1 > 9) {
hex1 &= 223;
hex1 -= 7;
}
int hex2 = in[i + 2] - '0';
if (hex2 > 9) {
hex2 &= 223;
hex2 -= 7;
}
*((unsigned char *) &in[out]) = (unsigned char) (hex1 * 16 + hex2);
i += 2;
} else {
/* Is this even a rule? */
if (in[i] == '+') {
in[out] = ' ';
} else {
in[out] = in[i];
}
}
/* We always only write one char */
out++;
}
/* If decoded string is shorter than original, put null char to stop next read */
if (out < statementValue.length()) {
in[out] = 0;
}
return statementValue.substr(0, out);
}
} else {
/* This querystring is invalid, cannot parse it */
return {nullptr, 0};
}
}
queryString.remove_prefix(statement.length() + 1);
}
/* Nothing found is given as nullptr, while empty string is given as some pointer to the given buffer */
return {nullptr, 0};
}
}
#endif